Part of [ENG-5153](https://linear.app/comm/issue/ENG-5153)
Depends on D9451
Finally we can split the endpoints:
- webapp only hosts html, css, js and other related files
- keyserver contains keyserver logic, websocket etc.
We need to add a redirect for uploads from the webapp to the keyserver because previously the urls had the origin of `web.comm.app` instead of `squadcal.com`. As mentioned in the previous diff I don't think it's worth migrating them because:
- we still need to support older clients with old urls
- we will be migrating to blob in the future anyway
Note: landing this diff needs to be delayed like D9291, because web clients need to be reloaded to connect to squadcal